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4.2 Soil Salinity and Yield of Boro Rice and Rabi Crops as Practiced by the Farmers in
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3.84 dS/m at vegetative stage, 7.80 dS/m at reproductive stage and 7.05 dS/m at ripening stage for BRRI Dhan-47 in Khona village. The EC of soil was 3.50 dS/m at vegetative stage, 6.92 dS/m at reproductive stage and 6.46 dS/m at ripening stage for BRRI Dhan 47 in Khatail village. The yield of BRRI Dhan-47 was 3.50 t/ha in Khona and 3.00 t/ha in Khatail. In the BRRI practice the yield of BRRI Dhan-47 was 6.0 t/ha and the threshold EC of soil is 8 dS/m for BRRI Dhan-47 (Huq and Rabbani, 2011). The EC of soil was 3.17 dS/m at vegetative stage, 6.96 dS/m at reproductive stage and 6.05 dS/m at ripening stage for BRAC-5 (Shakti- 2) in Lokmikhola village. The EC of soil was 3.47 dS/m at vegetative stage, 6.49 dS/m at reproductive stage and 6.18 dS/m at ripening stage for BRAC-5 (Shakti-2) in Pankhali village. The yield of BRAC-5 (Shakti-2) was 5.90 t/ha in Lokmikhola and 2.90 t/ha in Pankhali. The EC of soil was 3.81 dS/m at vegetative stage, 7.09 dS/m at reproductive stage and 6.72 dS/m at ripening stage for BINA Dhan-8 in Pankhali village. The yield of BINA Dhan-8 was 4.00 t/ha in Pankhali. In the BINA practice, the yield of BINA Dhan-8 was 5.5 t/ha under salt stresses (BINA, 2010). From the discussion with farmers, due to the severe pest attack, the yield was 2.90 t/ha for the Hybrid variety of Boro rice BRAC-5 (Shakti-2) in Pankhali village. In the BRAC practice, the yield of Hybrid variety of Boro rice, Shakti-2 (BRAC-5) was 7.6 t/ha (Rashid et al., 2011). In spite of applying pesticides, the farmers could not get the desired yield of Shakti-2 (BRAC-5). The threshold EC of soil is 10 dS/m for BINA Dhan-8 (BINA, 2010). The threshold EC of soil is 10 dS/m for Shakti-2 (Rashid et al., 2011)
The EC of soil varied from the vegetative stage to ripening stage for the all Boro rice variety.
The EC of soil decreased at ripening stage than reproductive stage. From the analysis of rainfall, it was found the amount of rainfall was 33 mm at ripening stage and 5 mm at reproductive stage. There was the variation of yield according to the variety. The highest yield was 4.8 t/ha for the variety of BINA Dhan-8. In spite of having the EC of soil at tolerant level the yield decreased. From the discussion with farmers, the farmers applied more fertilizer than recommended level. The excess fertilizer increased the vegetative growth of rice, hampered the reproductive growth of rice and ultimately decreased the yields. In the study area, most of the farmers selected the Hybrid variety of Boro rice Shakti-2 (BRAC-5).
Because of the NGO motivated the farmers by training and supplying the seeds.
The farmers of both Channirchalk and Shaharabad village cultivated the BINA Dhan-8. The DAE motivated the farmers to cultivate BINA Dhan-8 in Polder 32. The BINA Dhan-8
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variety is more salt tolerant than BRRI Dhan-47. The Polder 32 was cyclone Aila affected area and more saline than Polder 31.The EC of soil was 3.80 dS/m at vegetative stage, 6.79 dS/m at reproductive stage and 8.70 dS/m at ripening stage in Channirchalk village. The EC of soil was 3.67 dS/m at vegetative stage, 5.98 dS/m at reproductive stage and 7.93 dS/m at ripening stage in Shaharabad village. The yield of BINA Dhan-8 in Channirchalk and Shaharabad was 4.00 t/ha and 4.5 t/ha respectively. The average EC of soil was 3.74 dS/m at vegetative stage, 6.38 dS/m at reproductive stage and 8.31 dS/m at ripening stage. From the analysis of rainfall, it was found the amount of rainfall was 33 mm at ripening stage and 5 mm at reproductive stage. In spite of having salinity at tolerant level the yield decreased because the farmers did not follow the recommended fertilizer.
The EC of soil was high at vegetative, reproductive and ripening stage in Polder 32 than Polder 31. In spite of having same amount of rainfall both in Polder 31 and Polder 32, the EC of soil increased at ripening stage in Polder 32 than Polder 31.
The maximum farmers cultivated the local variety of sesame. Because of the seed of local variety of sesame was available in the local market. A few of farmers cultivated the BARI Til 4. Since, they got the seed of BARI Til-4 from DAE as an experimental plot. The EC of soil was 4.1 dS/m at vegetative stage, 8.04 dS/m at reproductive stage and 6.85 dS/m at ripening stage in Khatail village. The EC of soil was 3.93 dS/m at vegetative stage, 8.03 dS/m at reproductive stage and 5.56 dS/m at ripening stage in Khona village. The EC of soil was 3.61 dS/m at vegetative stage, 7.36 dS/m at reproductive stage and 6.88 dS/m at ripening stage in Lokmikhola village. The average EC of soil was 3.88 dS/m at vegetative stage, 7.81 dS/m at reproductive stage and 6.43 dS/m at ripening stage. A few of farmers cultivated the sesame in Polder 32. The EC of soil was 4.13 dS/m at vegetative stage, 8.21dS/m at reproductive stage and 6.36 dS/m at ripening stage in Kamarkhola village of Polder 32.
The EC of soil varied from vegetative stage to ripening stage for the local variety of sesame.
The EC of soil decreased at ripening stage than reproductive stage. The EC of soil at vegetative stage, reproductive stage and ripening stage of sesame and the yield of sesame are shown in the Table 4.2.
From the analysis of rainfall, it was found the amount of rainfall was 33 mm at ripening stage and 5 mm at reproductive stage. In Khatail, Khona and Lokmikhola, the yield was 0.80 t/ha, 0.71 t/ha and 0.75 t/ha respectively. In BARI practice, the yield of sesame was 1.3 t/ha. From
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the discussion with farmers, the farmers did not apply irrigation due to lack of irrigation water. Also, the farmers applied less fertilizer than BARI recommended practice. So, the yield decreased due to the lack of irrigation water and proper nutrition.
Table 4.2: Comparison between EC of soil, variety and yield of sesame (variety: local) in Polder 31 and Polder 32
Name of the Union
Name of the location
EC (dS/m) of soil at vegetative
stage (Feb 20- March 30)
EC (dS/m) of soil at reproductive
stage (March 31-
April 30)
EC (dS/m) of soil at
ripening stage (May 01 -
May 20)
Threshold EC (dS/m)
of soil
Yield (t/ha)
Pankhali (Polder 31)
Khatail 4.1 8.04 6.85
6.0
0.80
Khona 3.93 8.03 5.56 0.71
Lokmikhola 3.61 7.36 6.88 0.75
Average 3.88 7.81 6.43
Kamarkhola
(Polder 32) Kamarkhola 4.13 8.21 6.36 0.60
The EC of soil at vegetative stage, pre-flowering stage and heading stage of sunflower and the yield of sunflower are shown in the Table 4.3. From the farmers practice, the EC of soil was 2.22 dS/m at vegetative stage, 4.36 dS/m at pre-flowering stage and 6.53 dS/m at heading stage in Khatail village. The EC of soil was 2.62 dS/m at vegetative stage, 4.77 dS/m at pre-flowering stage and 6.94 dS/m at heading stage in Khona village. The EC of soil was 2.65 dS/m at vegetative stage, 4.82 dS/m at pre-flowering stage and 7.01 dS/m at heading stage in Lokmikhola village. The EC of soil was 2.34 dS/m at vegetative stage, 4.80 dS/m at pre-flowering stage and 6.90 dS/m at heading stage in Kamarkhola village. The average EC of soil was 2.50 dS/m at vegetative stage, 4.65 dS/m at pre-flowering stage and 6.82 dS/m at heading stage. Most of the farmers cultivated the Hysun-33 variety of sunflower. The seed of the Hysun-33 variety was supplied by the BRAC. A few of farmers cultivated the sunflower in Polder 32. The EC of soil was 2.34 dS/m at vegetative stage, 4.80 dS/m at pre-flowering stage and 6.90 dS/m at heading stage in Kamarkhola village of Polder 32. The threshold EC of soil is 6.0 dS/m (SRDI, 2014) for sesame.
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Table 4.3: Comparison between EC of soil, variety and yield of sunflower (variety: Hysun- 33) in Polder 31 and Polder 32
Name of the Union
Name of the location
EC (dS/m) of soil at vegetative
stage (Jan 20 –
Feb 20)
EC (dS/m) of soil at pre-
flowering stage (Feb 21 –
Mar 22 )
EC (dS/m) of
soil at heading
stage (Mar 23 –
April 21)
Threshold EC (dS/m)
of soil
Yield (t/ha)
Pankhali (Polder 31)
Khatail 2.22 4.36 6.53
4.8
1.7
Khona 2.62 4.77 6.94 0.7
Lokmikhola 2.65 4.82 7.01 1.3
Average 2.50 4.65 6.82
Kamarkhola
(Polder 32) Kamarkhola 2.34 4.80 6.90 0.8
From the analysis of rainfall, it was found the amount of rainfall was 24 mm at flowering stage and 5 mm at heading stage. So, the EC of soil increased at heading stage than flowering stage. In Khatail, Khona, Lokmikhola and Kamarkhola village, the yield was 1.7 t/ha, 0.7 t/ha, 1.3 t/ha and 0.8 t/ha respectively. The potential yield of sunflower was 2 t/ha (according to BRAC). The farmers got the lower yield than the previous years because they applied less fertilizer than BARI recommended doses. The threshold EC of soil is 4.8 dS/m (FAO, 2001) for sunflower.
4.3 Intensity of Water Salinity in the Sources of Irrigation Water in Different Locations